Drill point fastener

ABSTRACT

A fastener may include an elongated shank, a head at a distal end of the shank, and a drill point at a terminal end of the shank, which is opposite to the distal end. The fastener may include a primary thread starting at the drill point and extending along the shank towards the head. The fastener may include a secondary thread starting at the drill point, extending along the shank towards the head, and stopping in an axial direction before the primary thread ends. The secondary thread may be radially located 180 degrees from the primary thread. The drill point may include a plurality of radially extending cutting edges and one or more relieved flute portion extending along the surface of the drill point.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of application Ser. No.14/958,243, filed Dec. 3, 2015, now allowed; which claims priority toU.S. Provisional Application No. 62/147,443, filed on Apr. 14, 2015, andto Taiwan Utility Model Patent Application 104208950 filed on Jun. 5,2015, the entirety of which are incorporated by reference in thisapplication.

TECHNICAL FIELD

Certain example embodiments described herein relate generally tofasteners. More particularly, certain example embodiments describedherein relate to fasteners, such as screws, for securing a plurality ofobjects together and to methods of their manufacture.

BACKGROUND AND SUMMARY

Fasteners have been designed in many shapes, sizes, and configurationsfor joining two or more objects together. Screws and bolts are some ofthe more commonly used fasteners for joining objects. Most screws andbolts fall under the category of externally threaded fasteners whichinclude external threads (e.g., male threads) wrapped around a cylinderextending from a head of the fastener. Externally threaded fasteners maybe designed for assembly with a nut or an object having a nut threadmatching the thread of the fastener. Other externally threaded fastenersmay have ends designed for insertion into a hole (e.g., a pre-drilledpilot hole, punched hole, or nested hole) or may have an end with apierce-point that is designed to penetrate a surface of the object to bejoined. A pierce point, also known as a needle point, speed point orsprint point, provides a sharp end point that is configured to piercethe surface to be joined.

A fastener with a pierce point may be used, for example, to join sheetmetal to other objects. As the pierce point of the fastener piercesthrough the sheet metal, the thread of the fastener engages and drivesthe fastener through the layer(s) of the sheet metal and, if provided,into other object(s) with ease and great speed.

In applications where the fastener is exposed to elements (e.g., weatherelements) that may corrode the fastener, the fastener is coated with aprotective material layer (e.g., paint, zinc, or copper). Unfortunately,however, during the process of coating the fastener, the sharpness ofthe end point may be compromised due to deposits of the coating materialon the end point. In addition, during the process of coating thefastener, due to processes involved in the coating, a heavier layer ofmaterial may be deposited on the polar ends of the fastener. While suchheavier deposition of the material on the head end of fastener may nothave an adverse effect, a thick coating on a pierce point rounds offwhat should be a sharp point. This rounding causes the pierce-point tobe less effective in quickly piercing the surface to be fastened and insome cases may not even allow the surface to be pierced. Such roundingof the pierce-point is particularly observed during an electroplatingprocess that causes a heavier layer of material (e.g., zinc) to beformed on the ends of the fastener than the center portion of thefastener including the threads.

Certain example embodiments address these and/or other concerns. Forinstance, certain example embodiments relate to a fastener with a pointend geometry that is less affected by unequal distribution of a coatingmaterial. Certain example embodiments provide a fastener with aself-drilling point that allows for quick fastener installation. Thegeometry of the self-drilling point reduces the undesired buildup ofcoating material on the end of the fastener.

In certain example embodiments, a fastener may include an elongatedshank, a head at a distal end of the shank, and a drill point at aterminal end of the shank, which is opposite to the distal end. Thefastener may include a primary thread starting at the drill point andextending along the shank towards the head. The fastener may include asecondary thread starting at the drill point, extending along the shanktowards the head, and stopping in an axial direction before the primarythread ends. The secondary thread may be radially located 180 degreesfrom the primary thread. The drill point may include a plurality ofradially extending cutting edges and one or more relieved flute portionsextending along the surface of the drill point.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages may be better and morecompletely understood by reference to the following detailed descriptionof exemplary illustrative embodiments in conjunction with the drawings,of which:

FIGS. 1-4 illustrate exemplary embodiments of a fastener according tovarious embodiments of the present disclosure;

FIG. 5 illustrates an exemplary embodiment of a fastener according toanother embodiment of the present disclosure; and

FIG. 6 illustrates a method of manufacturing a fastener according to anembodiment of the present disclosure.

DETAILED DESCRIPTION

Fasteners have been used in the construction industry for years tosecure roof and/or wall sheeting material to structural framing. Forexample, in post-frame construction, exterior walls made of roll-formedcorrugated metal panels may be secured to a wood structural frame(vertical wooden posts and horizontal wooden trusses) using hardenedsteel fasteners. These fasteners may include a hex head, a rubber and/ora steel washer, sharp and deep crested threads along the shank (e.g.,which may be one to three inches in length), and a very sharp-point. Thefastener may be installed with an electric screw-gun fitted with ahexagonal socket that fits the head of the fastener. During installationof the fastener, the sharp-point of the fasteners is placed at the pointof attachment on the corrugated metal panel. As pressure is applied tothe fastener, the screw gun is activated and the sharp-point penetratesthe panel. Once the panel is penetrated, the deep crested threads engagewith the wood substructure until the full length of the shank has tappedcompletely and the rubber washer is compressed against the panel tocreate a seal. The sharpness of the pierce point (e.g., a gimlet point)and the thread definition at the point's apex is critical to thefastener's ability to penetrate the metal panel. Should the point beblunted or of a spherical shape after manufacturing, the performancewill be less than acceptable or, in some cases, will not penetrate thepanel at all.

The fasteners may be made of hardened carbon steel. They may also bepainted to match the color of the corrugated metal panel. The fastenersmay need to have measurable and consistent dimensional aspects, as wellphysical values that include tensile strength, ductility, and hardness.The fasteners may be designed so as to provide for quick installationinto the metal panel and/or wood/metal frame.

The fasteners, which are installed on the exterior of the post-framestructure, should also be resistant to the corrosive effects of acidrain, temperature extremes, UV rays, etc. Thus, the hardened steelfasteners (e.g., carbon steel fasteners) may be coated prior to use inorder to protect them from environmental conditions that will causerusting of their surface. Manufacturers typically protect the fastenersfrom corrosion by galvanizing the surface. The galvanizing can beapplied in one of three methods: hot dipping (which is typically notused for post-frame fasteners); mechanical plating; or electroplating.Mechanical plating is a process in which a coating is applied to thefasteners by tumbling them with in a mixture of water, a metallic powder(e.g., zinc powder) and chemicals until a predetermined thickness ofmetallic coating has accumulated on the fastener's surface.

The electroplating process, as the name implies, subjects a quantity offastener to an electric current in the presence of, for example, zincions dispersed in an electrolyte. During this process, a predeterminedcurrent density applied to the system creates an electromagnetic fieldaround the fastener. The zinc ions are electrically attracted to thefastener and are deposited in a tight, adherent film over the surface ofthe fastener.

Variations in current density, length of the fastener, surface area ofthe fastener, time of exposure, and other factors may determine thethickness of the metal coating. These variables may be considered inpredetermining the time required to deposit a given thickness of metalcoating onto the surface of the fastener. However, the metal coating maynot be deposited uniformly over the entire surface of the fastener. Thepolar effect of the electromagnetic field tends to deposit more metalcoating at the polar ends, that is, the head portion and the pointportion of the fastener. Consequently, less metal coating is depositedat the axial midpoint of the fastener. The operator of theelectroplating system tends to use the axial midpoint as his referencepoint to assure that the minimum specified metal coating thickness isdeposited at the midpoint of the fastener.

Thickness measurements taken at three selected locations, that is, thehead, the axial mid-length, and the point apex, confirm the non-uniformdistribution of metal coating along the axial length. The metal coating(e.g., zinc) thickness on the head portion of the fastener varies from1.5 to as high as 3.5 times the metal coating thickness measured at themid-length. Similarly, thickness of metal coating (e.g., zinc) at thepoint apex has shown to vary from 5 to as high as 8 times the thicknessof metal coating measured at mid-length of the fastener.

In most cases, this extra metal coating thickness on the head of thefastener does not adversely affect the installation performance. Thisextra thickness tends to enhance the corrosion resistance since the headof the fastener is the only portion of the fastener exposed toweathering conditions. However, the disproportionately greater thicknessof the metal coating at the point apex adversely affects the fastener'sability to pierce a surface of a first object (e.g., a metal panel)and/or subsequent objects during installation.

The polar attraction may be essentially equal at both poles of thefastener during the electroplating process. However, because the surfacearea of the polar point is very small compared to the polar head of thefastener, the metal coating tends to form a spherical ball comparable toa ball-point pen instead of a uniform layer. During the attemptedinstallation, this spherical point allows the fastener to rotate freelyon the surface of first object (e.g., surface of a steel panel) insteadof quickly piercing the steel panel.

Observations and measurements confirm that reducing the difference insurface area of the polar ends tends to mitigate the adverse effects ofdisproportionate distribution of the metal coating (e.g., zinc). Becausethe surface area of the polar ends affects the distribution of metalcoating on the respective ends, increasing the surface area of the pointend should allow more uniform distribution of the metal coating withoutthe spherical build-up of metal coating and thereby improve thefastener's ability to penetrate the steel panel.

As discussed in more detail below, in some of the embodiments of thepresent disclosure, a point geometry was selected that provides twocutting edges radially displaced at 180 degrees terminating at anintersection that does not include a sharp point apex provided byexisting fasteners. The two cutting edges may be offset slightly toallow removal of steel sheeting as soon as rotation of the fastenerbegins. The result is that the fastener can penetrate the steel sheetalmost immediately without freely spinning as was the case with a sharppoint of existing fasteners. Test results have shown that, in theembodiment discussed below, there is no excessive non-functional metalcoating buildup that would prevent the fastener from penetrating thesheeting as intended. The thickness of metal coating (e.g., zinc) at thecutting edges at the end of the drill point fastener was significantlyreduced when compared to a sharp pointed fastener.

FIGS. 1-4 illustrate an exemplary embodiment of a fastener 10 accordingto an embodiment of the present disclosure. The fastener 10 may includean elongated shank 12, a head 14 at a distal end of the shank 12, and adrill point 16 at a terminal end of the shank 12, which is opposite tothe distal end. The fastener 10 may include a plurality of threads 18,20 provided along the shank 12. A first thread 18 may be formedextending along the shank 12 on a first portion and a second portion ofthe shank 12. A second thread 20 may be formed extending along the shank12 on the second portion of the shank 12.

The first thread 18 may begin axially at a first location L1 below thehead 14 at the distal end and continue to a predetermined secondlocation L2 axially remote from the distal end and the first locationL1. The first thread 18 may continue past the second location L2 and toa predetermined third location L3 axially remote from the distal end andthe second location L2. The predetermined third location L3 may be inthe vicinity of the terminal end of the shank 12. The second thread 20may begin axially at the second location L2 and continue to thepredetermined third location L3. As shown in FIGS. 3A and 3B, the firstthread 18 and the second thread 20 may be helically wound along the axisand around the periphery of the shank 12.

A thread major diameter 18 a and/or a thread pitch of the first thread18 may remain constant between the first location L1 and the secondlocation L2. Past the second location L2, the thread major diameter 18 aand/or the thread pitch of the first thread 18 may be changed. Forexample, past the second location L2, the thread major diameter 18 a ofthe first thread 18 may be reduced from a first value to a predeterminedsecond value, which is different from the first value. Similarly, pastthe second location L2, the pitch of the first thread 18 may be reducedfrom a first thread pitch value to a predetermined second thread pitchvalue, which is different from the first thread pitch value. The threadpitch of the first and second threads 18, 20 between the second locationL2 and the third location L3 may be equal.

The thread major diameter 18 a of the first thread 18 may be graduallyreduced from the first value to the predetermined second value in thevicinity of the second location L2. Between second location L2 and thethird location L3 the major diameter 18 a and/or the thread pitch of thefirst thread 18 may remain constant. At the third location L3, the firstthread 18 may taper at a predetermined angle relative to the axis of thefastener 10 and terminate in the vicinity of the third location L3. Thefirst thread 18 may taper and terminate at a predetermined locationaxially remote from the point apex with a smooth run-out unto anextended cylindrical portion of the drill point 16.

A thread major diameter 20 a and/or a thread pitch of the second thread20 may remain constant between the second location L2 and the thirdlocation L3. The thread major diameter 20 a of the second thread 20 maybe equal to the reduced thread major diameter 18 a (i.e., thepredetermined second value). Thus, the thread major diameter 20 a of thesecond thread 20 and the thread major diameter 18 a of the first thread18 may both be equal between the second location L2 and the thirdlocation L3. The second thread 20 may be radially located 180 degreesfrom the first thread 18 (e.g., terminate on opposite sides of thesurface of the shank 12). The second thread 20 may extend axially at amid-pitch of the first thread 18. At the third location L3, the secondthread 20 may taper at a predetermined angle relative to the axis of thefastener 10 and terminate in the vicinity of the third location L3. Thesecond thread 20 may taper and terminate at a predetermined locationaxially remote from the point apex with a smooth run-out unto anextended cylindrical portion of the drill point 16. The second thread 20may taper at a predetermined angle that is the same as the angle atwhich the first thread 18 tapers at the third location L3.

The minor diameter 22 of the first and second threads 18 and 20 may bethe same between the first location L1 and the second location L2 andbetween the second location L2 and the third location L3. In oneembodiment, the minor diameter of the first and second threads 18 and 20between the second location L2 and the third location L3 may be smallerthan the minor diameter of the first threads 18 between the firstlocation L1 and the second location L2.

The drill point 16 may have a predetermine diameter 16 a and axiallength 16 b. In one embodiment, the diameter of the drill point 16 a maybe smaller than the minor diameter 22 of the first and/or second threads18, 20. A conical taper may be provided between the minor diameter 22and the predetermine diameter 16 a of the drill point 16. In anotherembodiment, the diameter 16 a of the drill point 16 a may be the same asthe minor diameter 22 of the first and/or second threads 18, 20. In oneembodiment, the predetermine diameter 16 a of the drill point 16 may beequal to the axial length 16 b of the drill point 16. In anotherembodiment, the axial length 16 b of the drill point 16 may be greaterthan the predetermine diameter 16 a of the drill point.

The drill point 16 may include two radially extending cutting edges 24a, 24 b spaced apart approximately 180 degrees and sloping axially fromthe terminal end to an intersecting location on an outer surface of theshank 12. As used herein, approximately may refer to being almost, butnot exactly, 180 degrees. In one embodiment, the drill point 16 mayinclude more than two radially extending cutting edges (e.g., three orfour).

A first relieved flute portion 26 may extend axially from one of thecutting edges 24 a, 24 b and intersect or abut the thread run-out fromat least one of the first and second thread 18, 20. In one embodiment,the first relieved flute portion 26 may extend axially from one of thecutting edges 24 a, 24 b and intersect or abut the thread run-out fromthe first thread 18 and a second relived flute portion (not shown) mayextend axially from the other one of the cutting edges 24 a, 24 b andintersect or abut the thread run-out from the other second thread 20. Asshown in FIG. 1, the first and second thread may be run over a back edgeof the flute 26 to allow the threads to quickly engage the object afterthe drill point 16 penetrates the object. In one embodiment, a length ofthe flute portion 26 may be equal to the axial length 16 b of the drillpoint 16. In another embodiment, a length of the flute portion 26 may begreater than the axial length 16 b of the drill point 16.

The cutting edges 24 a, 24 b of the drill point 16 may be non-concurrentand/or non-interesting, such that, for example, the cutting edges 24 a,24 b do not form a point apex (e.g., a single sharp point) at theterminal end of the fastener. The cutting edges 24 a, 24 b may beoff-set from each other in a radial direction of the shank 12 so as tocreate a cutting action as soon as rotation of the fastener is started.During installation, the drill point 16 may be provided into a preformedaperture in an object (e.g., sheet metal) or create such an aperture asit is rotationally forced against the object.

In one embodiment, the thread major diameter 18 a of the first thread 18and the thread major diameter 20 a of the second thread 20 at the secondposition may have a first value (e.g., value of the thread majordiameter 18 a between the first and second locations) and gradually bereduced in the axial direction away from the distal end until the threadmajor diameters 18 a and 20 a taper and terminate at the drill point 16.

As shown in FIG. 4, a sealing washer 42 may be disposed around a portionof the shank 12 and against the head 14 of the fastener 10. The sealingwasher 42 may include a resilient sealing element 42 b and/or a cap 42a. The sealing element 42 b may, for example, be made of natural orsynthetic rubber. The cap 42 a may, for example, be a non-resilientwasher. The cap 42 a may be a steel washer. The resilient sealingelement 42 b may be vulcanized to the cap 42 b to form a seal thatprevents leaking even when the fastener is driven at an angle. In oneembodiment, the sealing washer 42 may be a single washer (e.g., rubberwasher). The resilient sealing element 42 b may be an elastomericrubber-like material for use as a sealing washer that will resist thedegrading effects of ultraviolet radiation and ozone in the atmosphere.The sealing element when compressed may allow for the sealing materialto flow unrestrained into internal voids that are inherently present inan assembly with the fastener. The sealing element(s) may allow for thefastener and the sealing element(s) to provide a weather-tight functionfor a desired number of years consistent with companion materials usedin the construction of the building.

The fastener 10 may be screwed into a first object 44 and into a secondobject 46 that is adjacent to the first object 44. The first object 44may be, for example, plastic, sheet metal, or composite material. Thesecond object 46 may be, for example, wood, metal structure, sheetmetal, plastic. As shown in FIG. 4, when the fastener 10 is screwed intothe first object 44 and the second object 46, a surface of the firstobject 44 is secured against a surface of the second object 46. Inaddition, the head 14 of the fastener 10 forms a seal with the sealingwasher 42, and the sealing washer 42 forms a seal with a surface of thefirst object 44. While in FIG. 4, the surface of the first object 44 isprovided against the surface of the second object 46 in the vicinity ofthe fastener 10, in some embodiments, a space may be provided betweenthe surface of the first object 44 and the surface of the second object46 in the vicinity of the fastener 10.

In one embodiment, the head 14 may have a shape designed to cooperatewith the structure of sealing washer 42. The head 14 may be formed witha torque-receiving portion 14 a for receiving torque with atorque-applying tool. In one embodiment, the head 14 may include arecess 14 b for receiving torque with a torque-applying tool. Thetorque-receiving portion 14 a may sit against an annular flange 14 c onthe shank side of which is formed an annular, tapered portion 30 (e.g.,a frusto-conical tapered portion). The tapered portion 30 may have aconical figure with a base abutting the torque receiving portion 14 aand/or the annular flange 14 c. The frustum of the tapered portion 30may join to an end of the shank 12. The tapered portion may provide fora washer 42 to be self-centered during assembly. As shown in thefigures, the annular flange 14 c may include a flat portion on eachside. The flange is not limited to this configuration and may includeconfigurations having other shapes. For example, the flange may have aflat shape on one side and/or a cupped shape on the opposite side toprovide the head 14 with a cupped head configuration for receiving atleast a portion of the washer 42 provided under the head 14.

FIG. 5 illustrates an exemplary embodiment of a fastener according toanother embodiment of the present disclosure. Features of the embodimentof the fastener shown in FIG. 5 may be combined with one or more featureof the fastener shown in FIGS. 1-4. As shown in FIG. 5, in addition to afirst thread 18 being formed on the shank 12 at the distal end of thefastener, a third thread 50 may be formed on the shank 12 at the distalend of the fastener. The third thread 50 may be radially located 180degrees from the first thread 18. The third thread 50 may extend alongthe shank 12 from the first location L1 and towards the drill point 16.The third thread 50 may extend towards the drill point 16 for a shortdistance (e.g., one eights of the length of the shank 12). The thirdthread 50 may extend towards the drill point 16 and stop before thesecond thread 20 starts at the second location L2. The first and thirdthreads may both stop at the same axial location of the shank but beoffset by 180 degrees (e.g., terminate on opposite sides of the surfaceof the shank 12).

Utilizing the third thread 50 may provide for the sealing washer 42 tobe positioned against the annular flange 14 c after assembly. Athickness of the sealing washer 42 may be made equal to the pitchbetween the first thread 18 and the third thread 50. Such thickness ofthe sealing washer 42 may allow the sealing washer 42 to fit between thefirst and third thread while being mounted on the fastener. When thesealing washer 42 is fully inserted on the fastener, it can bepositioned such that the plane of the sealing washer 42 is substantiallyperpendicular to the axis of the shank 12. In addition, once the sealingwasher 42 is fully inserted on the fastener, the first and third threadsmay support the sealing washer 42 in place and against the annularflange 14 c. Accordingly, the slippage of the washer or gasket from theposition in which it is located at the head of the fastener can bereduced.

The fastener 10 may be coated with a protective material. In oneembodiment, the fastener 10 may be made of steel or iron and may becoated with a protective zinc coating via galvanization. In otherembodiments, the fastener may be coated with a material viaelectrodepositing, electroplating, electro-galvanizing, and/ormechanical plating.

The relationship of the first thread 18 and the second thread 20 mayprovide benefits in the installation and the installed structuralstrength of the fastener. The construction industry is sensitive to thespeed in which the components of a building can be installed. Disruptionin the speed of installation may be costly to the builder. In addition,when metal sheeting (e.g., first object 44) is attached to framing(e.g., second object 46), a weather-tight seal is desired to remain fora relatively long period of time. Fasteners that are structurallyinferior can often be loosened after installation by wind forces actingagainst the underside of the wall and/or roof sheeting causing theweather-tight seal between the fastener and the sheeting to becompromised. Moisture from wind driven rain can undesirably enter thebuilding causing damage to its contents and deterioration of thestructural framing components.

The drill point 16 having a drill point that begins generally at thepoint apex and is of a sharpness and hardness that has been proven,through practice, provides for consistent penetration of a surface of anobject (e.g., metal sheeting) in a short period of time (e.g., anaverage time of 0.2 to 0.3 seconds). As the drill point 16 clears apilot hole, the threads 18 and 20 may contact and engage the steel paneland advance into the substrate. When the thread 18 and 20 have a samepitch, a symmetrical support may be provided to the fastener shank 12 toallow the initial threading engagement into the steel to be smooth anduninterrupted. As the fastener advances through the sheeting and intothe structural substrate, the uniform height of threads 18 and 20 mayprovide equilateral support to the fastener shank 12 to prevent thefastener from being installed at an undesirable acute angle to thesheeting. As the fastener further advances into the structuralsubstrate, the threads 18 and 20 may transition to a different height(e.g., thread major diameter 18 a), and follow the helical groovestarted in the substrate by the previously engaged threads. Theincreased height of thread may allow for deeper radial engagement of theuninterrupted substrate material thereby providing higher withdrawalstrength to the installed fastener. The helical groove may also preventexcessive unsymmetrical lateral forces on the fastener shank 12 toprevent the fastener from being installed at an undesirable acute angleto the metal panel being fastened. The withdrawal strength is furthersupplemented by the ratio of the radial diameter of the second threadradial diameter to the smaller radial diameter of the shank.Accordingly, the design of the fastener according to embodiment of thepresent disclosure is beneficial to the construction personnel becausethey provide for quick installation that is accurate and provides adesired hold over extended periods of time.

FIG. 6 illustrates a method of manufacturing a fastener according to anembodiment of the present disclosure. As shown in FIG. 6, a blank 60 maybe extruded having an elongated shank 62, a head 64 at a distal end ofthe shank 62, and an end point 66 at a terminal end of the shank 62. Theblank 60 may be provided between two dies that are disposed at the endpoint 66 of the blank 60 to form a drill point. As shown in FIG. 6,after the dies are applied to the end point 66 of the blank 60, thedrill point is formed with pointing scarp 70 attached to the end point66.

With the drill point formed, the plurality of threads (e.g., the firstthread, the second thread and/or the third thread discussed above) areformed with a threading machine that applied a plurality of dies to theblank 60 that have a mold of the threads to be applied to the fastener.The dies may include all of the threads (i.e., the first and secondthreads) that will be formed on the blank 60. The pointing scarp 70 maybe removed by the dies forming the thread on the blank. With the drillpoint and the threads formed, the fastener may be heat treated toprovide desired metal characteristics and coated with a material (e.g.,galvanized or electroplated).

The design of the fastener and/or the manufacturing process may alsoprovide benefits in the manufacturing of the fastener. For example,typically the taper to the apex of the gimlet point and the threadsalong the shank are performed by the single operation of the thread die.Manufacturing the fastener in the manner discussed above may be dividedamong three operations, as the tapering of the blank and pinching of thedrill point may be done in separate stages, prior to the tapered screwblank with the pinched drill point entering the threading operation.Such manufacturing process may prolong the useful life of the thread dieas it does not undergo the stress of displacing large amounts of steelneeded to roll pinch a gimlet point. Thus, the thread dies will not dulland wear out as quickly, and instead remain sharper, longer, providingscrew threads with smooth consistently sharp edges throughout themanufacturing operation. Such manufacturing process will also eliminatethe operation of a slot cut near the tip to remove a spiral shavinginherent as the gimlet point screw advances through the steel panel.This slotting operation is difficult to control and may yieldunpredictable results, often cutting the point of the fastener and/ordisrupting the initial drilling thread. In addition, during installationof standard fasteners, the spiral shaving often times remains intact,embedding itself and compromising the sealing washer and creating asource for moisture infiltration. The drill point discussed above willcreate shavings that are much smaller and may eliminate this problem oftrapping the spiral shaving, allowing the washer to seal as intended.

In one embodiment, the fasteners discussed above may be used inpost-frame construction where buildings are constructed with a woodstructural frame (vertical wooden posts and horizontal wooden trusses)and exterior walls made of roll-formed corrugated metal panels. Thepanels being affixed to the wooden substructure with the fasteners.However, the fasteners according to the various embodiments discussedabove are not limited to post-frame construction and may be used inother applications.

While the embodiment of the present disclosure have been described inconnection with what is presently considered to be the most practicaland preferred embodiment, it is to be understood that the invention isnot to be limited to the disclosed embodiment, but on the contrary, isintended to cover various modifications and equivalent arrangementsincluded within the spirit and scope of the appended claims. Also, thevarious embodiments described above may be implemented in conjunctionwith other embodiments, e.g., aspects of one embodiment may be combinedwith aspects of another embodiment to realize yet other embodiments.Further, each independent feature or component of any given assembly mayconstitute an additional embodiment.

We claim:
 1. A fastener comprising: an elongated shank; a head at adistal end of the shank, the head adapted for receiving torque to rotatethe fastener; a drill point at a terminal end of the shank, which isopposite to the distal end; a primary thread starting at the drill pointand extending along the shank towards the head at the distal end of theshank; and a secondary thread starting at the drill point, extendingalong the shank towards the head, and stopping in an axial directionbefore the primary thread ends, wherein the secondary thread is radiallylocated 180 degrees from the primary thread, and the drill pointincluding a plurality of radially extending cutting edges and one ormore relieved flute portions extending along the surface of the drillpoint.
 2. The fastener of claim 1, wherein a pitch of the primary threadis equal to a pitch of the secondary thread at least along a portion ofthe shank where the threads are radially located 180 degrees from eachother.
 3. The fastener of claim 2, wherein a pitch of the primary threadbetween the head and the stopping location of the secondary thread isgreater than the pitch of the primary thread between the stoppinglocation of secondary thread and the drill point.
 4. The fastener ofclaim 1, wherein a thread major diameter of the primary thread is equalto a thread major diameter of the secondary thread along a portion ofthe shank where the threads are radially located 180 degrees from eachother.
 5. The fastener of claim 4, wherein a thread major diameter ofthe primary thread between the head and the stopping location of thesecondary thread is greater than the thread major diameter of theprimary thread between the stopping location of secondary thread and thedrill point.
 6. The fastener of claim 1, wherein the drill pointincludes two radially extending cutting edges that are spaced apartapproximately by 180 degrees.
 7. The fastener of claim 6, wherein thedrill point includes two relieved flute portions, one relieved fluteportion extending axially from one of the cutting edges and abutting orintersecting a thread run-out from the primary thread, and the otherrelieved flute portion extending axially from the other cutting edgesand abutting or extending a thread run-out of the secondary thread. 8.The fastener of claim 1, wherein the plurality of cutting edges arenon-concurrent and are offset from each other in a radial direction ofthe shank.
 9. The fastener of claim 1, further comprising a sealingwasher disposed around a portion of the shank and against the head. 10.The fastener of claim 1, further comprising a third thread starting at alocation along the shank between the head and the stopping location ofthe secondary thread, extending along the shank towards the head, andradially located 180 degrees from the primary thread.
 11. A fastener forjoining an object to another, comprising: a proximal head having aportion adapted for receiving torque to rotate the fastener; an annulartapered portion joined to the torque receiving portion; and a shankportion joined to and extending from the annular tapered portion, theshank portion having a first thread and a second thread, the shankterminating at a distal tapered drill point remote from the headportion, the tapered point adapted to extend through a preformedaperture in the object or to create such aperture as it is rotationallyforced against the object, the first thread having a beginning at thetapered drill point and spirally extending along the periphery of theshank at a defined pitch and terminating at a predetermined first axiallocation from underside of the head, the second thread having abeginning at the tapered drill point and extending spirally along theperiphery of the shank at the predetermined pitch, the second threadbeing located between convolutions of the first thread and terminatingat a predetermined second axial location from underside of the head, thefirst thread and the second thread having a radially extended height,the height of the first thread transitionally increasing from a firstheight to a second height at a predetermined axial location in a planenormal to the axis of the shank and transitionally decreasing from thesecond height until it merges flush into the shank, the second threadtransitionally increasing from the first height to the second height atthe predetermined axial location in a plane normal to the axis of theshank, the second thread transition being essentially coplanar with thefirst thread transition, and the second thread spirally extendinguninterruptedly at the second heights to the predetermined axiallocation.
 12. The fastener as claimed in claim 11 wherein the first andthe second threads begin in a plane normal to the axis of the shank, andthe first thread and the second thread beginning is coplanar.
 13. Thefastener as claimed in claim 11 wherein the first thread and the secondthread beginnings are radially spaced from each other by 180 degrees.14. The fastener as claimed in claim 11 in which the pitch of the firstthread is the same as the pitch of the second thread.
 15. The fasteneras claimed in claim 14 in which the second thread is located equidistantfrom adjacent convolutions of the first thread.
 16. A fastening systemcomprising: a fastener for joining an object to another, comprising: aproximal head having a portion adapted for receiving torque to rotatethe fastener; an annular tapered portion joined to the torque receivingportion; and a shank portion joined to and extending from the annulartapered portion, the shank portion having a first thread and a secondthread, the shank terminating at a distal tapered drill point remotefrom the head portion, the tapered point adapted to extend through apreformed aperture in the object or to create such aperture as it isrotationally forced against the object, the first thread having abeginning at the tapered drill point and spirally extending along theperiphery of the shank at a defined pitch and terminating at apredetermined first axial location from underside of the head, thesecond thread having a beginning at the tapered drill point andextending spirally along the periphery of the shank at the predeterminedpitch, the second thread being located between convolutions of the firstthread and terminating at a predetermined second axial location fromunderside of the head, the first thread and the second thread having aradially extended height, the height of the first thread transitionallyincreasing from a first height to a second height at a predeterminedaxial location in a plane normal to the axis of the shank andtransitionally decreasing from the second height until it merges flushinto the shank, the second thread transitionally increasing from thefirst height to the second height at the predetermined axial location ina plane normal to the axis of the shank, the second thread transitionbeing essentially coplanar with the first thread transition, and thesecond thread spirally extending uninterruptedly at the second heightsto the predetermined axial location; and a sealing washer having athrough-bore aperture and positioned with the fastener shank extendingthrough the aperture, the washer being located at the terminus of thesecond thread and being supported by the thread termini from freelymoving axially along the shank and thereby being undesirably displacedaxially toward the fastener distal end.
 17. The fastening system asclaimed in claim 16 wherein the washer is a one-piece resilientelastomeric material and is disposed against the head including a cuppedhead configuration.
 18. The fastening system as claimed in claim 16wherein the washer is of bonded metal and elastomeric materialconstruction disposed under the flat head of the fastener.